CategorizeNumbers - LINQ

            var integers = new List<int>();
            var floatingPointNumbers = new List<double>();

            Console.ReadLine()
                .Split()
                .Select(double.Parse)
                .ToList()
                .ForEach(number =>
                {
                    if (number % 1 == 0)
                    {
                        integers.Add((int) number);
                    }
                    else
                    {
                        floatingPointNumbers.Add(number);
                    }
                });